1. Field of the Invention
The present invention relates to a stacking tray device, particularly a stacking tray device to be used for a business machine.
2. Description of the Prior Art
Paper size is determined according to a specific ratio of width to length. Presently, the most widely used standard in the world is stipulated by the ISO, which names paper sizes A4, B5, etc. The international standard for paper sizes can be divided into three types: A, B and C. The unique feature of said standard lies in the fact that the ratio of length to width for paper sizes is √2 (approximately 1.4142). Differently sized paper of the same type have the same proportion, and therefore can be directly resized or photocopied without cropping the edges of the content on a page.
Currently in the U.S.A., Canada, Mexico, Bolivia, Colombia, Venezuela, the Philippines and Chile the official paper size is the Letter (LTR), also called the US Letter, which is 8.5 inches by 11 inches (215.9 mm by 279.4 mm). The Letter paper standard is adopted by the American National Standards Institute, while the A4 size (210 mm by 297 mm) is the ISO standard and is used by many countries. Letter paper is slightly shorter and wider than A4 paper. Generally speaking, the widest paper size is continuous form paper, which is 9.5 inches by 11 inches (241.3 mm by 279.4 mm), with holes along both the left and right edges of the paper.
Most business machines, such as fax machines, printers, copy machines, etc., are equipped with an open tray, whereupon the user may place paper and feed the paper into the business machine for copying, faxing or printing. There are various paper types and sizes, and when a small document is fed into a business machine with a larger feeding opening, the document becomes easily skewed. Skewing not only leads to inaccuracies in the output image, but also due to uneven pressure the paper may be wrinkled or damaged in the paper feeding process, a situation which should be avoided at all costs. Thus, trays on most business machines are equipped with two guide plates, such that when paper is placed in the space between said two guide plates, the distance between the two guide plates may be adjusted to match the width of the paper and restrict the width of the feeding opening, thus positioning the paper in the very center and preventing skewing from occurring during the paper feeding process. With conventional technology, the distance between the two guide plates is adjusted to the maximum before paper is placed on the tray. After paper is placed on the tray, the two guide plates are slowly retracted until they come into contact with the edge of the paper. The above method is both inconvenient and inaccurate.
Another conventional technology consists of labeling the tray with various paper sizes, such that the user can first adjust the two guide plates by aligning them with the appropriate label on the tray, and then place the paper on the tray. This method requires the user to carefully and deliberately move the guide plates and is therefore inconvenient.
Thus, there exists a need on the market for a new stacking tray device, which can reduce the occurrence of paper skewing during the paper feeding process and meet user demands for intuitive operation.